Train yourself to take the 20 minutes required to learn to "do it the right way" every time you need to. Its so easy not to bother because you are busy but in the long run you will save time.
I think this is the right answer, assuming OP actually wants to get better at bash and not route around his original question by learning stuff that isn't bash.
I use bash/shell scripts frequently and have many running 'in production' as cron jobs th at run various jobs or manipulate data for other jobs to run on.
One thing I really like about pure shell is that it's extremely portable and transparent about what it's doing.
I still have to re-learn control structures almost everytime I write a new script, I don't try and memorize [[]] vs [] and all the weird ways equality can work, I just google each time and answers are always on top (once you know what you're looking for).
and keep a set of text files for yourself where after learning to do it the right way you write it down. I find that especially with bash/command line things I don't have to solve the same problem often (which would help with remembering) but often enough to be annoying having to re-learn it all the time, so it really pays off to have some documentation to refer to. org-mode and vimwiki are quite good for that.
